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Madhumitha Mahadevan, Scott Stevenson; Effect of attention on cyclovergence and cycloversion eye movements.. Journal of Vision 2017;17(10):274. doi: https://doi.org/10.1167/17.10.274.
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This study aimed to determine the effect of spatial attention on torsional eye responses. Verbal instructions were used to ask the subjects to pay attention to one of two torsion stimuli to determine if the instructions had any effect on cyclovergence and cycloversion response amplitudes. The stimuli consisted of a fixation dot, an inner disk, and an outer annulus, each filled with static random dots. Diameters of the fixation dot, the central disk and the annulus were 0.5 degrees, 40.3 degrees and 80.6 degrees respectively. Dots in the central disk and annulus rotated 5 degrees back and forth about the central fixation with a frequency of 0.25 or 0.5 Hz. Four conditions were run to balance attention and frequency across field position. Dots seen by left and right eyes rotated in the same (cycloversion) or opposite (cyclovergence) directions. Subjects (N = 6) wore red – green anaglyph glasses and were asked to hold their head and gaze steady on the central fixation dot and pay attention to the torsion motion of the disk and ignore the annulus or vice versa. Scleral search coils were used to record eye position at 500 Hz. Fourier analysis was used to determine the tracking amplitude at each frequency for each condition. We observed consistent responses to both vergence and version stimuli in all subjects for both frequencies, with an overall average tracking gain of 0.08. Instruction to attend or ignore made a roughly 2x change in version responses in 3 subjects, a 1.25 change in a 4th subject and no change in a 5th and 6th subject. No subject showed a change in cyclovergence responses with attention. The results of this study suggest that the mechanisms controlling cyclovergence are outside the influence of attentional enhancement.
Meeting abstract presented at VSS 2017
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